The present invention concerns a method of increasing the strength of wood by impregnating it with a polymerizable liquid.
According to some prior art methods the wood is initially introduced into a container which is evacuated for removal from the wood of moisture and gases (air). The container is thereafter filled with a liquid containing a polymerizable monomer and/or oligomer, and the wood is impregnated with this liquid under pressure. The polymerization of the polymerizable liquid to convert it to a plastic is thereafter carried out by means of radioactive radiation for approximately 24 hours, usually with the aid of a cobalt gun.
A method of this kind suffers from several disadvantages. The method is expensive on account of the polymerization through radiation. The acquisition of a cobalt gun also means that considerable capital must be invested. In order to effect the polymerization process very rapidly as possible the generated radiation may be too strong, which means degradation of the wood and damage thereof. Consequently, it is necessary that great care is exercised and the intensity of the radiation is delimited, which on the other hand has the negative result of prolonging the polymerization process, normally up to some 24 hours.